Oren Jacoby’s Constantine’s Sword, which opens today at the Belcourt, takes a careful and extensive look at a subject that almost always invokes strong reactions whenever discussed: religion.

It is based on the book Constantine’s Sword: The Church and the Jews: A History, which was written in 2001 by acclaimed and award-winning author, journalist and former Catholic James Carroll. Carroll’s also the focal point of the documentary.

His primary focus involved examining the roots of Anti-Semitism within the Catholic Church, though he extends his study into many other areas. The film contains lengthy portions devoted to the Crusades and Inquisition, and explores links between religion and intolerance, violence and war.

Though clearly unhappy and dissatisfied in many ways with the faith that was once the centerpiece of his life, Carroll is quick to disavow any notion he doesn’t consider religion important, nor understand the value and impact it still enjoys in many people’s lives.

Carroll also ponders why so many ugly and negative things have been done in the name of religion. He focuses on such key figures as Pope Pius XII and Pope Benedict XVI, discussing what he sees as gross failures to address issues ranging from the Holocaust to more recent sex scandals.

There’s also a conversation with Ted Haggard, who when he spoke with Carroll was the pastor of the New Life Megachurch. Haggard later had to step down after a scandal involving a male prostitute, something that makes some of his comments rather suspect.

But Carroll never comes across as combative or angry. Instead, he’s inquisitive and truly interested in seeking answers to complex difficult questions.

Raised in a devout (and military) home, Carroll had to decide whether to follow the father he idolized and join the Air Force (his father was a general) or pursue the priesthood, which he ultimately selected. But his ardent anti-war views led to clashes with papal authority plus an estrangement from his father.

Carroll was eventually ousted from his position as priest in the early ‘70s, though he’s since participated in many interfaith gatherings over the years between Catholics, Jews and Muslims. He maintains friendships and relationships with his former church, and considers himself a disillusioned rather than lapsed Catholic.

Constantine’s Sword is outstanding investigative reporting. Whether the setting is Germany, Rome, or in Carroll’s former home in Colorado, there are consistently insightful discussions and exchanges.

No matter your views on religion and its place in society, Oren Jacoby’s film offers plenty of information and opinion to carefully consider, debate and analyze.

Constantine’s Sword
Directed by: Oren Jacoby
Starring: James Carroll
Rating: No rating
Time: 93 minutes
Our view: Magnificent and thorough, examining a vital subject with clarity and in a fair, if at times controversial, fashion.